• 미생물학회지
• /
• 제25권2호
• /
• pp.110-116
• /
• 1987

고도 카드뮴 내성효모 Hansenula anomala B-7의 균체내에 다량의 카드뮴을 축적시키기 위하여 배양시 계면활성제를 첨가하여 배양하는 방법을 검토했다. 계면활성제 중 비이온계인 Triton X-100에 의하여 약 40%의 카드뮴의 축적효과를 나타내며 유효농도는 0.1-0.2%였다. 균체내 카드뮴 축적의 최적조건은 다음과 같다. 정치배양보다 진탕배양이 효과적이었으며, 48시간 진탕배양으로 카드뮴의 균체내 축적이 최대에 도달했으며 배지의 초기 pH는 6.0이었으며, 배양온도는 $40^{\circ}C$가 양호했다.

• Journal of Microbiology and Biotechnology
• /
• 제9권2호
• /
• pp.140-146
• /
• 1999

When methanol was the sole carbon source, Methylobacterium organophilum NCIB 11278, a facultative methylotroph, accumulated Poly-$\beta$-hydroxybutyrate (PHB) as 59% (w/w) of dry cell weight under potassium limitation, 37% under sulfate limitation, and 33% under nitrogen limitation. Based on a stoichiometric analysis of PHB synthesis from methanol, it was suspected that PHB synthesis is accompanied by the overproduction of energy, either 6-10 ATP and 1 $FADH_2$ or 6 ATP and 3 NADPH to balance the NADH requirement, per PHB monomer. This was confirmed by observation of increased intracellular ATP levels during PHB accumulation. The intracellular ATP with limited potassium, sulfate, and ammonium increased to 0.185, 0.452, and 0.390 $\mu$moles ATP/g Xr (residual cell mass) during PHB accumulation, respectively. The intracellular ATP level under potassium limitation was similar to that when there was no nutrient limitation and no PHB accumulation, 0.152- 0.186 $\mu$moles ATP/g Xr. We propose that the maximum PHB accumulation observed when potassium was limited is a result of the energy balance during PHB accumulation. Microorganisms have high energy requirements under potassium limitation. Enhanced PHB accumulation, in ammonium and sulfate limited conditions with the addition of 2,4-dinitrophenol, which dissipates surplus energy, proves this assumption. With the addition of 1 mM of 2,4-dinitrophenol, the PHB content increased from 32.4% to 58.5% of dry cell weight when nitrogen limited and from 15.1 % to 31.0% of dry cell weight when sulfate limited.

• Archives of Pharmacal Research
• /
• 제19권2호
• /
• pp.132-136
• /
• 1996

Exogenously applied oxygen free radical generating agent, pyrogallol, highly elevated extracellular glutamate accumulation and augmented N-methyl-D-aspartate (NMDA)-induced glutamate accumulation in cerebellar granule neuronal cells, but did not in astrocytes. Superoxide dismutase remarkably decreased the pyrogallol-induced glutamate accumulation, but either NMDA or kainate antagonists did not. In addition, pyrogallol did not affect the NMDAinduced intracellular calcium elevation. Pyrogallol partially blocked glutamate uptake into astrocytes. These results suggest that oxygen free radicals elevate extracellular glutamate accumulation by stimulating the release of glutamate as well as blocking the glutamate uptake.

• 한국미생물·생명공학회지
• /
• 제18권3호
• /
• pp.233-238
• /
• 1990

The mechanism of intracellular accumulation of cadmium in a cadmium-ion tolerant yeast, Hansenula ammala B-7, which is an extreme cadmium tolerant strain and has the ability to take up a large amount of cadmium was investigated. The amounts of cadmium taken up by the scalded yeast cells were 2 to 3 times more than the value of the living cells. The living Hansenula anomala B-7 cells adsorbed 74% of cadmium taken up onto the other layer of the cells and 26% of it accumulated inside the cells. But the scalded cells adsorbed 98.3% of cadmium taken up and accumulated 1.7% of it inside the cells. A cadmium uptake and its accumulation were accelerated up to 162.3% and 275.4% by Triton X-100 in the living cells, respectively. Whereas in the scalded cell cadmium uptake was not affected by Triton X-100. Furthermore the cadmium uptake and its accumulation were strongly inhibited by metabolic inhibitors like 2,4-dinitrophenol, sodium azide and potassium cyanide in the living cells, but in the scalded cells cadmium uptake was not affected by metabolic inhibitors. These results suggested that the intracellular accumulation of cadmium by the cadmium-tolerant Hansenula anomala B-7 cells was apparently dependent of biological activity, and also gave evidence of the existance of energy-dependent system.

• The Korean Journal of Physiology and Pharmacology
• /
• 제1권5호
• /
• pp.537-546
• /
• 1997

It has been postulated that the intracellular taurine is co-transported with $Na^+$down a concentration gradient and prevents the intracellular accumulation of sodium. It is therefore, expected that an elevated level of intracellular taurine prevents the sodium-promoted calcium influx to protect the cellular damages associated with sodium and calcium overload. In the present study, we evaluated the effects of intra- and extracellular taurine on the myocardial $Na^+$and$Ca^{++}$ contents and the cardiac functions in isolated rat hearts which were loaded with sodium by monensin, a $Na^+-ionophore$. Monensin caused a dose-dependent increase in intracellular $Na^+$ accompanied with a subsequent increase in intracellular $Ca^{++}$ and a mechanical dysfunction. In this monensin-treated heart, myocardial taurine content was decreased with a concomittent increase in the release of taurine. The monensin-induced increases in intracellular $Na^+$, $Ca^{++}$ and depression of cardiac function were prevented in the hearts of which taurine content had been increased by high-taurine diet. Conversely, in the hearts of which taurine concentration gradient had been decreased by addition of taurine in the perfusate, the monensin-induced increases in $Na^+$, $Ca^{++}$ and functional depression were accelerated. These results suggest that taurine, depending on the intra-extracellular concentration gradient, can affect intracellular sodium and calcium concentrations, and that an increased intracellular taurine may play a role in protection of myocardial dysfunction associated with the sodium and calcium overload.

• 대한의생명과학회지
• /
• 제24권2호
• /
• pp.64-75
• /
• 2018

CCN3 (also known as NOV, Nephroblastoma overexpressed) proteins are involved in various pathologies during different developmental stages. We have previously shown that intracellular levels and normal extracellular secretion of CCN3 are important for neuronal differentiation. Furthermore, we demonstrated that a single amino acid in the CCN3 TSP-1 domain is important for extracellular secretion and that palmitoylation of CCN3 is required in this process. However, the effect of abnormal CCN3 accumulation on cells remains to be studied. Here, we found mutations in the TSP-1 domain of CCN3 that led to intracellular accumulation and abnormal aggregation of CCN3. It was observed that this mutation resulted in a phenomenon similar to neurodegeneration when overexpressed in the developing mouse cortex. This mutation also confirmed the activation of apoptotic gene expression in Neuro2a cells. In addition, we confirmed the in vivo transcriptional changes induced by this mutation using microarray analysis. We observed a significant increase in the expression of Anp32a, an apoptosis-related gene. Collectively, these results indicate that a single mutation in CCN3 can lead to abnormal cell death if it shows intracellular accumulation and abnormal aggregation.

• Fisheries and Aquatic Sciences
• /
• 제15권1호
• /
• pp.21-27
• /
• 2012

Ground seawater in the east area of the volcanic Jeju Island contains abundant minerals. We investigated the metabolic activity of electrodialyzed, desalted ground seawater (EDSW) from Jeju in both cultured cells and animals. The addition of EDSW to the culture medium (up to 20%, v/v) reduced the leakage of lactate dehydrogenase and increased MTT activity in CHO-IR cells. EDSW (10%) promoted insulin-induced glucose consumption in L6 muscle cells as well as the activities of the liver ethanol-metabolizing enzymes, alcohol dehydrogenase and aldehyde dehydrogenase. Moreover, EDSW suppressed palmitate-induced intracellular fat accumulation in human hepatoma $HepG_2$ cells. Activities of AMP-stimulated protein kinase and acetyl CoA carboxylase, enzymes that modulate fat metabolism, were altered by EDSW in $HepG_2$ cells toward the suppression of intracellular lipid accumulation. EDSW also suppressed hepatic fat accumulation induced by a high-fat diet in mice. Taken together, EDSW showed beneficial metabolic effects, including the enhancement of ethanol metabolism and insulin-induced glucose consumption, and the suppression of intrahepatic fat accumulation.

• The Korean Journal of Physiology and Pharmacology
• /
• 제22권2호
• /
• pp.215-223
• /
• 2018

Intracellular $Ca^{2+}$ mobilization is closely linked with the initiation of salivary secretion in parotid acinar cells. Reactive oxygen species (ROS) are known to be related to a variety of oxidative stress-induced cellular disorders and believed to be involved in salivary impairments. In this study, we investigated the underlying mechanism of hydrogen peroxide ($H_2O_2$) on cytosolic $Ca^{2+}$ accumulation in mouse parotid acinar cells. Intracellular $Ca^{2+}$ levels were slowly elevated when $1mM\;H_2O_2$ was perfused in the presence of normal extracellular $Ca^{2+}$. In a $Ca^{2+}-free$ medium, $1mM\;H_2O_2$ still enhanced the intracellular $Ca^{2+}$ level. $Ca^{2+}$ entry tested using manganese quenching technique was not affected by perfusion of $1mM\;H_2O_2$. On the other hand, $10mM\;H_2O_2$ induced more rapid $Ca^{2+}$ accumulation and facilitated $Ca^{2+}$ entry from extracellular fluid. $Ca^{2+}$ refill into intracellular $Ca^{2+}$ store and inositol 1,4,5-trisphosphate ($1{\mu}M$)-induced $Ca^{2+}$ release from $Ca^{2+}$ store was not affected by $1mM\;H_2O_2$ in permeabilized cells. $Ca^{2+}$ efflux through plasma membrane $Ca^{2+}-ATPase$ (PMCA) was markedly blocked by $1mM\;H_2O_2$ in thapsigargin-treated intact acinar cells. Antioxidants, either catalase or dithiothreitol, completely protected $H_2O_2-induced$ $Ca^{2+}$ accumulation through PMCA inactivation. From the above results, we suggest that excessive production of $H_2O_2$ under pathological conditions may lead to cytosolic $Ca^{2+}$ accumulation and that the primary mechanism of $H_2O_2-induced$ $Ca^{2+}$ accumulation is likely to inhibit $Ca^{2+}$ efflux through PMCA rather than mobilize $Ca^{2+}$ ions from extracellular medium or intracellular stores in mouse parotid acinar cells.

• Journal of Microbiology and Biotechnology
• /
• 제31권7호
• /
• pp.1035-1043
• /
• 2021

Although engineered Saccharomyces cerevisiae fermenting cellobiose is useful for the production of biofuels from cellulosic biomass, cellodextrin accumulation is one of the main problems reducing ethanol yield and productivity in cellobiose fermentation with S. cerevisiae expressing cellodextrin transporter (CDT) and intracellular β-glucosidase (GH1-1). In this study, we investigated the reason for the cellodextrin accumulation and how to alleviate its formation during cellobiose fermentation using engineered S. cerevisiae fermenting cellobiose. From the series of cellobiose fermentation using S. cerevisiae expressing only GH1-1 under several culture conditions, it was discovered that small amounts of GH1-1 were secreted and cellodextrin was generated through trans-glycosylation activity of the secreted GH1-1. As GH1-1 does not have a secretion signal peptide, non-conventional protein secretion might facilitate the secretion of GH1-1. In cellobiose fermentations with S. cerevisiae expressing only GH1-1, knockout of TLG2 gene involved in non-conventional protein secretion pathway significantly delayed cellodextrin formation by reducing the secretion of GH1-1 by more than 50%. However, in cellobiose fermentations with S. cerevisiae expressing both GH1-1 and CDT-1, TLG2 knockout did not show a significant effect on cellodextrin formation, although secretion of GH1-1 was reduced by more than 40%. These results suggest that the development of new intracellular β-glucosidase, not influenced by non-conventional protein secretion, is required for better cellobiose fermentation performances of engineered S. cerevisiae fermenting cellobiose.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2003년도 생물공학의 동향(XIII)
• /
• pp.730-735
• /
• 2003

본 실험에서는 분리된 곤충병원성 선충 6종의 온도에 따른 trehalose의 농도와 병원성의 상관관계를 조사하였으며 온도 적응, oil, glycerol을 이용하여 trehaolse 생성량 조절에 대하여 조사하였다. 저온에서는 S. longicaudum G1 종이 $81.92{\mu}g/mg$로 가장 높게 나타났으며, 고온에서는 S. glaseri Agr B3 $71.22{\mu}g/mg$로 가장 높게 나타났다. 또한 S. longicaudum G1을 저온에서 적응 시켰을 경우 병원성과 trehaolserk 향상되었으며 S. glaseri Agr B3 종일 경우 고온에 적응 시켰을 경우 역시 향상되었다. glycerol 20%과 oil 전 농도에서 처리하였을 경우 도 종 모두 다소 향상되는 것으로 나타났다.